Polymer Composition, Article Comprising Said Composition And Use Of Said Article

Abstract

The present invention relates to a polymer composition, comprising a polypropylene and a stabilizing additive mixture, wherein said stabilizing additive mixture comprises: i) a thioether compound according to Formula I, ii) a Hindered Amine Light Stabilizer (HALS) comprising a substituted amine group; and iii) an inorganic acid scavenger. The present invention further relates to an article comprising said polymer composition, and the use of said polymer composition for the housing for antennas for wireless communication.

Description

TECHNICAL FIELD

[0001] The present invention relates to a polymer composition comprising a polypropylene and a stabilizing additive mixture. The present invention further relates to an article comprising such a polymer composition, and the use of such a polymer composition for the housing for antennas for wireless communication.

BACKGROUND

[0002] Plastic housings for telecom communication antennas are known. There are several severe requirements to which the polymer compositions have to comply in order to be suitable for use in antenna housing, such as a high temperature resistance, good ultraviolet absorption resistance, good ageing resistance, good shock resistance, good insulating capacity, good crazing resistance, good corrosion resistance, and high mechanical and dimensional strength. These antenna housings may be located in a severe environment and should resist deformation and deterioration.

SUMMARY

[0003] It is an object of the present invention to provide a polymer composition with improved resistance to heat and weathering.

[0004] It is a further object of the present invention to provide an article with improved resistance to heat and weathering.

[0005] Corresponding embodiments are also applicable for the article and the use of an article according to the present invention.

[0006] One or more of these objects are achieved by a polymer composition, comprising a polypropylene and a stabilizing additive mixture, wherein said stabilizing additive mixture comprises: [0007] i) a thioether compound according to Formula I:

##STR00001##

[0008] wherein Q.sup.1 and Q.sup.2 are each independently an alkyl spacer having between 1 and 6 carbon atoms, preferably being --CH.sub.2CH.sub.2--; R.sup.1 and R.sup.2 each independently being an alkyl group having between 14 and 26 carbon atoms, preferably between 16 and 20 carbon atoms, such as --C.sub.18H.sub.37; O being oxygen and S being sulphur; [0009] ii) a Hindered Amine Light Stabilizer (HALS) comprising a substituted amine group; and [0010] iii) an inorganic acid scavenger.

[0011] A "substituted amine group" as used in the present description means a group comprising a nitrogen atom that is substituted with other atoms than hydrogen. In other words, no --N(--H)-- group. In an embodiment, the substituted amine group is an --N(--OR)-- group or an --N(--R)-- group wherein R is not a hydrogen.

[0012] It was surprisingly found that this above composition provides polymer products with improved heat resistance as well as weatherability and good dimensional and mechanical properties.

[0013] The invention further relates to an article comprising such a polymer composition, and to the use of such a polymer composition for the housing for antennas for wireless communication.

DESCRIPTION OF EMBODIMENTS

[0014] In an embodiment of the present invention, the polypropylene is a heterophasic propylene copolymer consisting of a propylene-based matrix and a dispersed ethylene-a-olefin copolymer. In a specific embodiment, the heterophasic propylene copolymer has a melt flow rate of between 0.1 and 10.0 g/10 min as determined in accordance with ISO 1133:1-2011 (230.degree. C., 2.16 kg). In a specific embodiment the heterophasic copolymer comprises between 70 and 90 wt % of said matrix and between 10 and 30 wt. % of said dispersed phase.

[0015] In an embodiment, Q.sup.1 and Q.sup.2 are each --CH.sub.2CH.sub.2--; R.sup.1 and R.sup.2 each --C.sub.18H.sub.37. This is a dialkyl ester of thiodipropionic acid, with CAS no: 693-36-7, and it is commercially available for instance under the name Irganox PS 802 FL from BASF.

[0016] In an embodiment, the substituted amine group in the HALS is a --N(R)-- group; wherein R is a hydrocarbyl group. In a specific embodiment, the HALS is according to Formula IIa or IIb

##STR00002## [0017] wherein: [0018] R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each independently an alkyl ground having 1-3 carbon atoms; [0019] R.sup.7 is --O--C(.dbd.O)--R.sup.9; [0020] L is --O--C(.dbd.O)--R.sup.10--C(.dbd.O)O-- [0021] R is either directly linked to the nitrogen atom (--R.sup.8) or connected via an oxygen atom (--OR.sup.8); [0022] R.sup.8 is an optionally substituted, optionally branched alkyl group having between 2 and 10 carbon atoms, such as between 3 and 5 carbon atoms; [0023] R.sup.9 is an alkyl group having between 4 and 14 carbon atoms; [0024] R.sup.10 is an alkyl group having between 4 and 14 carbon atoms.

[0025] In a further embodiment, in Formula IIa or IIb, R.sup.3.dbd.R.sup.4.dbd.R.sup.5.dbd.R.sup.6.dbd. methyl. In a further embodiment, in in Formula IIa or IIb, R.sup.8 is a branched alcohol group.

[0026] In a preferred embodiment, the HALS is a NOR-type hindered amine light stabilizer wherein the HALS is according to Formula IIa or IIb, wherein R is connected via an oxygen atom (--OR.sup.8); R.sup.8 is an optionally substituted, optionally branched alkyl group having between 2 and 10 carbon atoms, such as between 3 and 5 carbon atoms. It was surprisingly found a polymer composition comprising a NOR-type HALS has improved heat resistance and weatherability. For example, the NOR-type HALS has the following structure:

##STR00003##

[0027] NOR-type HALS is commercially available, for instance, Tinuvin.RTM. XT 855 FF from BASF.

[0028] In an embodiment, the inorganic acid scavenger is a hydrotalcite. In a preferred embodiment, this hydrotalcite is of the chemical family of aluminium-magnesium-carbonate-hydroxide (hydrate), with the following formula: Mg.sub.4.3Al.sub.2(OH).sub.12.6CO.sub.3-mH.sub.2O. This compound has CAS no. 11097-59-9, and is commercially available for instance as Hycite.RTM. 713 of Clariant.

[0029] In an embodiment, the composition further comprises a sterically hindered phenolic antioxidant. In a preferred embodiment this sterically hindered phenolic antioxidant is a polyphenolic antioxidant. In a preferred embodiment this polyphenolic antioxidant is tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), and is commercially available for instance as Irganox.RTM. 1010 from BASF.

[0030] In an embodiment, the composition further comprises a phosphite (secondary) antioxidant. In a preferred embodiment, this phosphite antioxidant is bis-t-butyl phenyl phosphite; and is commercially available for instance as Irgafos 168 from BASF.

[0031] In an embodiment, the thioether compound is present in an amount of between 0.10 and 1.0 wt. % of the total polymer composition. In a preferred embodiment the thioether compound is present in an amount of between 0.30 and 0.60 wt. % of the total polymer composition.

[0032] In an embodiment, the Hindered Amine Light Stabilizer is present in an amount of between 0.05 and 0.75 wt. % of the total polymer composition. In a preferred embodiment, the Hindered Amine Light Stabilizer is present in an amount of between 0.15 and 0.40 wt. % of the total polymer composition.

[0033] In an embodiment, the inorganic acid scavenger compound is present in an amount of between 0.05 and 0.75 wt. % of the total polymer composition. In an preferred embodiment, the inorganic acid scavenger compound is present in an amount of between 0.10 and 0.40 wt. % of the total polymer composition.

[0034] In an embodiment, the composition further comprises short glass fibre. In a preferred embodiment, the short glass fibre is present in an amount of between 15 and 50 wt. % of the total polymer composition, preferably at least 25 wt. %, more preferably at least 28 wt. %, preferably at most 35 wt. %, more preferably at most 32 wt. %; such as between 25 and 35 wt. % or between 28 and 32 wt. %.

[0035] In an embodiment, the article according to the invention is an outdoor article. In a preferred embodiment, the article is a housing for an antenna for wireless communication.

[0036] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The scope of the present invention is defined by the appended claims. One or more of the objects of the invention are achieved by the appended claims.

EXAMPLES

[0037] The present invention is further elucidated based on the Examples below which are illustrative only and not considered limiting to the present invention.

[0038] Methods

[0039] The composition in prepared by compounding in a twin screw extruder as pellets, then testing sample preparation is done by single screw extrusion using the prepared pellets.

[0040] Chalking grade is determined according to ISO4892-2, after 1000 hr weathering. The chalking grade is expressed in a number between 0 and 5, using the following definition: 0=unchanged, 1=very slight change, 2=slight change, 3=moderate change, 4=considerable change, 5=severe change.

[0041] The notched Izod impact strength is determined according to ISO 180 at 23.degree. C. Retention of the notched Izod impact strength is determined as the percentage of impact strength remaining after 1950 h at 150.degree. C.

[0042] Materials

[0043] All (comparative) examples comprise a polypropylene impact copolymer (PP-I1), being Yungsox 3003 of Formosa (CAS no. 9010-79-1), having a melt index of 0.35 g/10 min (determined according to ISO 1133:1-2011). This impact copolymer comprises 15.7 wt. % of dispersed phase. The total amount of ethylene-based units (C2) in the copolymer (TC2) is 8.3 wt. %. The amount of ethylene-based units (C2) in the dispersed phase (RCC2) is 52.9 wt. %

[0044] All (comparative) examples comprise a high stiffness impact copolymer (PP-I2), being Moplen EP5079 of LyondellBasell, with a melt flow rate (at 230.degree. C., 2.16 kg) of 0.5 g/10 min. (determined according to ASTM D1238-13). This impact copolymer comprises 13.5 wt. % of dispersed phase. The total amount of ethylene-based units (C2) in the copolymer (TC2) is 5.8 wt. %. The amount of ethylene-based units (C2) in the dispersed phase (RCC2) is 43.0 wt. %

[0045] All (comparative) examples comprise an ethylene octene copolymer as a toughening agent (TA), being Fortify C1055D of SABIC, with a melt flow rate (at 230.degree. C., 2.16 kg) of 2.2 g/10 min (at 190.degree. C., 2.16 kg) or 1.0 g/10 min (determined according to ASTM D1238-13), a density of 857 kg/m.sup.3 (ASTM D792-10(2015)) (determined according to ASTM D1238-13).

[0046] All (comparative) examples comprise a maleic anhydride modified homo polypropylene resin as compatibilizer (CP), being Bondyram 1010 by Polyram, with a melt flow rate (at 190.degree. C., 2.16 kg) of 200 g/10 min (determined according to ISO1133:1-2011), a density of 0.90 g/cm3 (determined according to ISO1183), a melting point of 160.degree. C. (determined with DSC), and a maleic anhydride concentration of 1.0% (determined with FTIR).

[0047] All (comparative) examples comprise a color master batch (CMB) with light grey color.

[0048] All (comparative) examples comprise short glass fiber (SGF) with CAS No. 65997-17-3 with sizing on surface to improve the compatibility of the short glass fiber and polypropylene. The short glass fiber has a diameter of 10 .mu.m and a length of 4 mm. It is available from Owens Corning (OVC.TM. Reinforcements) under the name Performax 249A-10C.

[0049] All (comparative) examples comprise a polyphenolic antioxidant (Phen.AO), being Irganox.RTM. 1010 (pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate)) available from BASF.

[0050] All (comparative) examples comprise a phosphite antioxidant (Phos.AO), being Irgafose.RTM. 168 (bis-t-butyl phenyl phosphite) available from BASF.

[0051] (Comparative) Examples 1, 5-8 comprise a thiosynergistic heat stabilizer, being Irganox.RTM. PS 802 FL by BASF (thioether). It is a dialkyl ester of thiodipropionic acid, with CAS no: 693-36-7.

[0052] (Comparative) Examples 1-4, 7-8 comprise a NOR-type (NOR HALS) hindered amine light stabilizer Tinuvin.RTM. XT 855 FF from BASF.

[0053] Comparative Example 5 comprises a high molecular weight N-H type (NH HALS 1) hindered amine light stabilizer, being Chimassorb2020 of BASF, with CAS no. 192268-64-7, with a molecular weight of 2,600-3,4-g/mol, a melting range of 120-150.degree. C., a volatility (determined with thermogravimetric analysis, in air at 20.degree. C./min) expressed as the temperature at 1% weight loss of 290.degree. C. and expressed as the temperature at 10% weight loss of 355.degree. C. The structural formula of this HALS is as follows.

##STR00004##

[0054] Comparative Example 6 comprises a mixture with its main component is low molecular weight N-H type HALS (NH HALS 2), further comprising a UV-absorber, the mixture being V703 by Cytec, with melting range 51-60.degree. C., a relative density of 1.160 (25.degree. C.) and a UV absorber wavelength range of 270-340 nm.

[0055] Comparative Examples 1-6 comprise an inorganic acid scavenger (Inorg.AS), being Hycite.RTM. 713 of Clariant, with CAS number: 11097-59-9 of the chemical family of aluminium-magnesium-carbonate-hydroxide (hydrate), with a molar ratio of MgO to Al.sub.2O.sub.3 of between 4 and 5. Comparative Example 7 comprises an organic acid scavenger (Org.AS), being calcium stearate.

[0056] All (comparative) examples comprise a high performance nucleating agent (NA) for polyolefins, being Hyperform HPN-68L of Milliken. All (comparative) examples comprise a fluoropolymer based processing additive (PA1), being Fluoro-polymer PPA2300 of Purvan, with a particle size of 25 mesh, bulk density of 0.72 g/cm.sup.3, a melting point of 60.degree. C., a volatile percentage (105.degree. C., 1 h) of 0.12%.

[0057] All (comparative) examples comprise a mold release agent (MR), being N,N'-ethylene bis stearamide, commercially available as Kenamide EBS of PMC biogenix or Crodamide ORV of Sichuan SIPO Chemical or Acrawax C of Lonza, with CAS No. 110-30-5. Typical properties of this compound are a flash point (COC) of 296.degree. C. and a fire point of 315.degree. C.

[0058] All (comparative) examples comprise as processing additive (PA2) an ultra-high molecular weight siloxane polymer, dispersed in polypropylene homopolymer, being MB50-001 Masterbatch of Dow Corning, with a siloxane content of 50%, further comprising an organic resin polypropylene. This compound improves the surface quality, such as smoothness and gloss.

[0059] The composition of all (comparative) examples is indicated in Table 1 below in wt. %.

TABLE-US-00001 Ex1 CE2 CE3 CE4 CE5 CE6 CE7 CE8 PP-I1 25.80 25.80 25.80 25.80 25.80 25.80 25.80 25.90 PP-I2 25.80 26.00 25.75 25.50 25.80 25.80 25.80 25.90 TA 7.00 7.00 7.00 7.00 7.00 7.00 7.00 7.00 CP 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 CMB 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 SGF 32.00 32.00 32.00 32.00 32.00 32.00 32.00 32.00 Phen. AO 0.30 0.50 0.75 1.00 0.30 0.30 0.30 0.30 Phos. AO 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 Thioether 0.40 n.p. n.p. n.p. 0.40 0.40 0.40 0.40 N-OR HALS 0.30 0.30 0.30 0.30 n.p. n.p. 0.30 0.30 N-H HALS1 n.p. n.p. n.p. n.p. 0.30 n.p. n.p. n.p. NH-HALS2 n.p. n.p. n.p. n.p. n.p. 0.30 n.p. n.p. Inorg. AS 0.20 0.20 0.20 0.20 0.20 0.20 n.p. n.p. Org. AS n.p. n.p. n.p. n.p. n.p. n.p. 0.20 n.p. NA 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 PA1 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 MR 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.55 PA2 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 n.p = not present

[0060] The retention of notched Izod impact strength, as well as the chalking grade are indicated below for all (comparative) examples.

TABLE-US-00002 Ex1 CE2 CE3 CE4 CE5 CE6 CE7 CE8 Retention (%) 80.8 51.5 52.6 64.2 78.5 75.7 72.5 86.9 Chalking 0 0 0 0 3 3 3 2 grade

[0061] By comparing Ex1 with CE2, CE3 and CE4, it becomes clear that the addition of a thioether compound according to Formula I leads to improved retention.

[0062] By comparing Ex1 with CE5 and CE6, it becomes clear that the presence of a NOR type HALS leads to improved retention and chalking grade compared to an NH type HALS.

[0063] By comparing Ex1 with CE7 and CE8, it becomes clear that the presence of an inorganic acid scavenger leads to an improved retention and chalking grade compared to an organic or no acid scavenger.

Claims

1. A polymer composition, comprising a polypropylene and a stabilizing additive mixture, wherein said stabilizing additive mixture comprises: i) a thioether compound according to Formula I: ##STR00005## wherein Q.sup.1 and Q.sup.2 are each independently an alkyl spacer having between 1 and 6 carbon atoms; R.sup.1 and R.sup.2 each independently being an alkyl group having between 14 and 26 carbon atoms; O being oxygen and S being sulphur; ii) a Hindered Amine Light Stabilizer comprising a substituted amine group; and iii) an inorganic acid scavenger.

2. The polymer composition according to claim 1, wherein the polypropylene is a heterophasic propylene copolymer consisting of a propylene-based matrix and a dispersed ethylene-.alpha.-olefin copolymer.

3. The polymer composition according to claim 2, wherein the heterophasic copolymer comprises between 70 and 90 wt. % of said matrix and between 10 and 30 wt. % of said dispersed-phase ethylene-.alpha.-olefin copolymer.

4. The polymer composition according to claim 1, wherein Q.sup.1 and Q.sup.2 are each --CH.sub.2CH.sub.2--; R.sup.1 and R.sup.2 each --C.sub.18H.sub.37.

5. The polymer composition according to claim 1, wherein in the substituted amine group in the HALS is a --N(R)-- group; wherein R is a hydrocarbyl group.

6. The polymer composition according to claim 5, wherein the Hindered Amine Light Stabilizer has a structure represented by Formula IIa or IIb ##STR00006## wherein: R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each independently an alkyl group having 1-3 carbon atoms; R.sup.7 is --O--C(.dbd.O)--R.sup.9; L is --O--C(.dbd.O)--R.sup.10--C(.dbd.O)O--; R is either directly linked to the nitrogen atom (--R.sup.8) or connected via an oxygen atom (--OR.sup.8); R.sup.8 is an optionally substituted, optionally branched alkyl group having between 2 and 10 carbon atoms; R.sup.9 is an alkyl group having between 4 and 14 carbon atoms; and R.sup.10 is an alkyl group having between 4 and 14 carbon atoms.

7. The polymer composition according to claim 1, wherein the inorganic acid scavenger is a hydrotalcite.

8. The polymer composition according to claim 1, wherein the composition further comprises a sterically hindered phenolic antioxidant.

9. The polymer composition according to claim 1, wherein the composition further comprises a phosphite antioxidant.

10. The polymer composition according to claim 1, wherein the thioether compound is present in an amount of between 0.10 and 1.0 wt. %, of the total polymer composition.

11. The polymer composition according to claim 1, wherein the Hindered Amine Light Stabilizer is present in an amount of between 0.05 and 0.75 wt. %, of the total polymer composition.

12. The polymer composition according to claim 1, wherein the inorganic acid scavenger compound is present in an amount of between 0.05 and 0.75 wt. %, of the total polymer composition.

13. The polymer composition according to claim 1, wherein the composition further comprises short glass fibre.

14. Article comprising the polymer composition of claim 1.

15. The article according to claim 14, wherein the article is a housing for antennas for wireless communication.

16. The polymer composition according to claim 6, wherein R.sup.3, R.sup.4, R.sup.5 and R.sup.6 are each methyl; and R.sup.8 is a branched alcohol group.

17. The polymer composition according to claim 1, wherein the composition further comprises a polyphenolic antioxidant.

18. The polymer composition according to claim 17, wherein the polyphenolic antioxidant is pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate).

19. The polymer composition according to claim 13, wherein the short glass fibre is present in an amount of 5 and 50 wt. % of the total polymer composition.

20. The polymer composition according to claim 13, wherein the short glass fibre is present in an amount of 25 and 35 wt. %, of the total polymer composition.